1. Field of the Invention
The present invention relates to an ink jet cleaning apparatus for cleaning an ink jet head which has a nozzle surface provided with orifices and which causes ink to be ejected from the orifices, as well as an ink jet recording apparatus provided with the ink jet head.
2. Discussion of the Background
An ink jet recording apparatus is provided with an ink jet head for ejecting ink as ink droplets from orifices formed in a nozzle surface toward a recording medium, with an image being recorded on the recording medium by the ink jet head. In such an ink jet recording apparatus, the ink jet head approaches the recording medium in a recording operation, so that the scattering of ink which is attributable to collision of ink droplets with the recording medium may contaminate the nozzle surface of the ink jet head. Particularly, in an on-demand type ink jet recording apparatus, ink droplet discharge energy is small, besides, the ink jet head is spaced several millimeters or so from the recording medium, so that the nozzle surface is apt to be contaminated by scattered ink, with consequent clogging of nozzles. Once there occurs nozzle clogging, it is difficult to clear up the clogging because pressure force for discharging the ink from the nozzle is small.
For preventing or avoiding the occurrence of such nozzle clogging there have been proposed a suction technique wherein all of plural orifices are hermetically sealed with a cap and a partial suction technique wherein orifices are partially subjected to suction (see Japanese Patent No. 3161050). There also has been proposed a technique wherein a nozzle surface is wiped using a cleaning member to remove ink and coagulations remaining on the nozzle surface (see Japanese Published Unexamined Patent Application No. 10-119311). Further, there has been proposed a technique wherein the number of times of wiping operations is changed according to an elapsed time after a sucking operation (see Japanese Published Unexamined Patent Application No. 2001-219567).
However, even in case of using any of the above suction techniques, there sometimes occurs a case where ink remains on the nozzle surface after the sucking operation, with the nozzle surface being contaminated. Such contamination of the nozzle surface results in adhesion to the same surface of fibers contained in the recording medium, as well as dust and dirt, causing nozzle clogging in a long period of use of the ink jet head, with consequent deterioration of ink jet stability for example. In case of using a suction technique, moreover, it is necessary that the sucking operation be carried out frequently in order to maintain the nozzle surface in a satisfactory condition. Consequently, there arises the problem that the energy consumption is high and a recording operation (printing operation) cannot be performed during each of frequent sucking operations.
Although the wiping technique is highly effective in removing foreign matters and coagulations adhered to the nozzle surface, there is a fear of the nozzle surface becoming worn due to contact therewith of a wiping member or damaged due to dragging of foreign matters or coagulations, which would deteriorate the nozzle surface condition or shorten the life of the ink jet head.